Measuring logs from a picture
A good machine learning object detector, would be helpful in finding the logs but classical image processing would be required to accurately find the log profiles.  Neural networks are generally not used for computing geometric dimensions.  In addition, you will need to have a calibration method so that you can convert pixels to some distance unit (e.g. inches, centimeters, etc.).  

The Timbeter app seems to do what you need (see below).



This app (see below)  is interesting although it doesn't solve your problem.  It appears good at counting but finding the profiles to within an inch is a bigger problem.



This blog "HOW MANY LOGS CAN A WOODCHUCK COUNT?" goes over the image processing challenges of counting logs.  The author doesn't completely solve the problem.

There is a post on Stackoverflow, How to count white object on Binary Image?
 which makes an attempt.